/*
 * Swipe 2.0
 *
 * Brad Birdsall
 * Copyright 2013, MIT License
 *
 */

function Swipe(container, options) {
	"use strict";

	// utilities
	var noop = function() {
	};
	// simple no operation function
	var offloadFn = function(fn) {
		setTimeout(fn || noop, 0)
	};
	// offload a functions execution

	// check browser capabilities
	var browser = {
		addEventListener : !!window.addEventListener,
		touch : ('ontouchstart' in window) || window.DocumentTouch && document instanceof DocumentTouch,
		transitions : (function(temp) {
			var props = ['transformProperty', 'WebkitTransform', 'MozTransform', 'OTransform', 'msTransform'];
			for (var i in props )
			if (temp.style[props[i]] !== undefined)
				return true;
			return false;
		})(document.createElement('swipe'))
	};

	// quit if no root element
	if (!container) return;
	
	var element = container.children[0];
	var slides, slidePos, width;
	options = options || {};
	var index = parseInt(options.startSlide, 10) || 0;
	var speed = options.speed || 300;
	options.continuous = options.continuous ? options.continuous : true;
	
	
	function setup() {

		// cache slides
		slides = element.children;

		// create an array to store current positions of each slide
		slidePos = new Array(slides.length);

		// determine width of each slide
		width = container.getBoundingClientRect().width || container.offsetWidth;

		element.style.width = (slides.length * width) + 'px';

		// stack elements
		var pos = slides.length;
		while (pos--) {

			var slide = slides[pos];

			slide.style.width = width + 'px';
			slide.setAttribute('data-index', pos);

			if (browser.transitions) {
				slide.style.left = (pos * -width) + 'px';
				move(pos, index > pos ? -width : (index < pos ? width : 0), 0);
			}

		}

		if (!browser.transitions) element.style.left = (index * -width) + 'px';

		container.style.visibility = 'visible';

	}

	function prev() {

		if (index)
			slide(index - 1);
		else if (options.continuous)
			slide(slides.length - 1);

	}

	function next() {

		if (index < slides.length - 1)
			slide(index + 1);
		else if (options.continuous)
			slide(0);

	}

	function slide(to, slideSpeed) {

		// do nothing if already on requested slide
		if (index == to)
			return;

		if (browser.transitions) {

			var diff = Math.abs(index - to) - 1;
			var direction = Math.abs(index - to) / (index - to);
			// 1:right -1:left

			while (diff--) move((to > index ? to : index) - diff - 1, width * direction, 0);

			move(index, width * direction, slideSpeed || speed);
			move(to, 0, slideSpeed || speed);

		} else {

			animate(index * -width, to * -width, slideSpeed || speed);

		}

		index = to;

		offloadFn(options.callback && options.callback(index, slides[index]));

	}

	function move(index, dist, speed) {

		translate(index, dist, speed);
		slidePos[index] = dist;

	}

	function translate(index, dist, speed) {

		var slide = slides[index];
		var style = slide && slide.style;

		if (!style)
			return;

		style.webkitTransitionDuration = style.MozTransitionDuration = style.msTransitionDuration = style.OTransitionDuration = style.transitionDuration = speed + 'ms';

		style.webkitTransform = 'translate(' + dist + 'px,0)' + 'translateZ(0)';
		style.msTransform = style.MozTransform = style.OTransform = 'translateX(' + dist + 'px)';

	}

	function animate(from, to, speed) {

		// if not an animation, just reposition
		if (!speed) {

			element.style.left = to + 'px';
			return;

		}

		var start = +new Date;

		var timer = setInterval(function() {

			var timeElap = +new Date - start;

			if (timeElap > speed) {

				element.style.left = to + 'px';

				if (delay)
					begin();

				options.transitionEnd && options.transitionEnd.call(event, index, slides[index]);

				clearInterval(timer);
				return;

			}

			element.style.left = (((to - from) * (Math.floor((timeElap / speed) * 100) / 100) ) + from) + 'px';

		}, 4);

	}

	// setup auto slideshow
	var delay = options.auto || 0;
	var interval;

	function begin() {

		interval = setTimeout(next, delay);

	}

	function stop() {

		delay = 0;
		clearTimeout(interval);

	}

	// setup initial vars
	var start = {};
	var delta = {};
	var isScrolling;

	// setup event capturing
	var events = {

		handleEvent : function(event) {

			switch (event.type) {
				case 'touchstart':
					this.start(event);
					break;
				case 'touchmove':
					this.move(event);
					break;
				case 'touchend':
					offloadFn(this.end(event));
					break;
				case 'webkitTransitionEnd':
				case 'msTransitionEnd':
				case 'oTransitionEnd':
				case 'otransitionend':
				case 'transitionend':
					offloadFn(this.transitionEnd(event));
					break;
				case 'resize':
					offloadFn(setup.call());
					break;
			}

			if (options.stopPropagation)
				event.stopPropagation();

		},
		start : function(event) {

			var touches = event.touches[0];

			// measure start values
			start = {

				// get initial touch coords
				x : touches.pageX,
				y : touches.pageY,

				// store time to determine touch duration
				time : +new Date

			};

			// used for testing first move event
			isScrolling = undefined;

			// reset delta and end measurements
			delta = {};

			// attach touchmove and touchend listeners
			element.addEventListener('touchmove', this, false);
			element.addEventListener('touchend', this, false);

		},
		move : function(event) {

			// ensure swiping with one touch and not pinching
			if (event.touches.length > 1 || event.scale && event.scale !== 1)
				return

			if (options.disableScroll)
				event.preventDefault();

			var touches = event.touches[0];

			// measure change in x and y
			delta = {
				x : touches.pageX - start.x,
				y : touches.pageY - start.y
			}

			// determine if scrolling test has run - one time test
			if ( typeof isScrolling == 'undefined') {
				isScrolling = !!(isScrolling || Math.abs(delta.x) < Math.abs(delta.y) );
			}

			// if user is not trying to scroll vertically
			if (!isScrolling) {

				// prevent native scrolling
				event.preventDefault();

				// stop slideshow
				stop();

				// increase resistance if first or last slide
				delta.x = delta.x / ((!index && delta.x > 0// if first slide and sliding left
				|| index == slides.length - 1// or if last slide and sliding right
				&& delta.x < 0 // and if sliding at all
				) ? (Math.abs(delta.x) / width + 1 )// determine resistance level
				: 1 );
				// no resistance if false

				// translate 1:1
				translate(index - 1, delta.x + slidePos[index - 1], 0);
				translate(index, delta.x + slidePos[index], 0);
				translate(index + 1, delta.x + slidePos[index + 1], 0);

			}

		},
		end : function(event) {

			// measure duration
			var duration = +new Date - start.time;

			// determine if slide attempt triggers next/prev slide
			var isValidSlide = Number(duration) < 250// if slide duration is less than 250ms
			&& Math.abs(delta.x) > 20// and if slide amt is greater than 20px
			|| Math.abs(delta.x) > width / 2;
			// or if slide amt is greater than half the width

			// determine if slide attempt is past start and end
			var isPastBounds = !index && delta.x > 0// if first slide and slide amt is greater than 0
			|| index == slides.length - 1 && delta.x < 0;
			// or if last slide and slide amt is less than 0

			// determine direction of swipe (true:right, false:left)
			var direction = delta.x < 0;

			// if not scrolling vertically
			if (!isScrolling) {

				if (isValidSlide && !isPastBounds) {

					if (direction) {

						move(index - 1, -width, 0);
						move(index, slidePos[index] - width, speed);
						move(index + 1, slidePos[index + 1] - width, speed);
						index += 1;

					} else {

						move(index + 1, width, 0);
						move(index, slidePos[index] + width, speed);
						move(index - 1, slidePos[index - 1] + width, speed);
						index += -1;

					}

					options.callback && options.callback(index, slides[index]);

				} else {

					move(index - 1, -width, speed);
					move(index, 0, speed);
					move(index + 1, width, speed);

				}

			}

			// kill touchmove and touchend event listeners until touchstart called again
			element.removeEventListener('touchmove', events, false)
			element.removeEventListener('touchend', events, false)

		},
		transitionEnd : function(event) {

			if (parseInt(event.target.getAttribute('data-index'), 10) == index) {

				if (delay)
					begin();

				options.transitionEnd && options.transitionEnd.call(event, index, slides[index]);

			}

		}
	}

	// trigger setup
	setup();

	// start auto slideshow if applicable
	if (delay)
		begin();

	// add event listeners
	if (browser.addEventListener) {

		// set touchstart event on element
		if (browser.touch)
			element.addEventListener('touchstart', events, false);

		if (browser.transitions) {
			element.addEventListener('webkitTransitionEnd', events, false);
			element.addEventListener('msTransitionEnd', events, false);
			element.addEventListener('oTransitionEnd', events, false);
			element.addEventListener('otransitionend', events, false);
			element.addEventListener('transitionend', events, false);
		}

		// set resize event on window
		window.addEventListener('resize', events, false);

	} else {

		window.onresize = function() {
			setup()
		};
		// to play nice with old IE

	}

	// expose the Swipe API
	return {
		setup : function(fn) {

			setup();
			if(fn){
				fn();
			}

		},
		slide : function(to, speed) {

			slide(to, speed);

		},
		prev : function() {

			// cancel slideshow
			stop();

			prev();

		},
		next : function() {

			stop();

			next();

		},
		getPos : function() {

			// return current index position
			return index;

		},
		kill : function() {

			// cancel slideshow
			stop();

			// reset element
			element.style.width = 'auto';
			element.style.left = 0;

			// reset slides
			var pos = slides.length;
			while (pos--) {

				var slide = slides[pos];
				slide.style.width = '100%';
				slide.style.left = 0;

				if (browser.transitions)
					translate(pos, 0, 0);

			}

			// removed event listeners
			if (browser.addEventListener) {

				// remove current event listeners
				element.removeEventListener('touchstart', events, false);
				element.removeEventListener('webkitTransitionEnd', events, false);
				element.removeEventListener('msTransitionEnd', events, false);
				element.removeEventListener('oTransitionEnd', events, false);
				element.removeEventListener('otransitionend', events, false);
				element.removeEventListener('transitionend', events, false);
				window.removeEventListener('resize', events, false);

			} else {

				window.onresize = null;

			}

		}
	}

}

if (window.jQuery || window.Zepto) {
	(function($) {
		$.fn.Swipe = function(params) {
			return this.each(function() {
				$(this).data('Swipe', new Swipe($(this)[0], params));
			});
		}
	})(window.jQuery || window.Zepto)
}
